This proposal is for a continuation of a long term project to define the pathological bases for hearing loss and dysequilibrium. Temporal bones from individuals with auditory or vestibular disorders will be prepared for light microscopic study and the findings correlated with the functional disorders. Additionally, some specimens will be studied by electron microscopy. The sets of prepared microscopic sections will be added to the teaching set for use by students, residents and visiting scientists. All significant pathology will be photographed for inclusion in the second edition of the book, Pathology of the Ear, programmed for publication in 1980.